Effect of solar radiation on the lipid characterization of biomass cultivated in high-rate algal ponds using domestic sewage

• Published in: Environmental technology Vol. 35; no. 18; pp. 2296 - 2305
• Main Authors: Assemany, Paula Peixoto, Calijuri, Maria Lúcia, Santiago, Aníbal da Fonseca, Couto, Eduardo de Aguiar do, Leite, Maurício de Oliveira, Bermudez Sierra, Jose Jovanny
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 17-09-2014; Taylor & Francis Ltd
• Subjects: adverse effects; Applied sciences; bacteria; Bacteria - chemistry; Bacteria - metabolism; biodiesel; Biofuels; Biological and medical sciences; Biomass; Bioreactors; Biotechnology; Chemical engineering; culture media; disinfection; domestic sewage; Drinking water and swimming-pool water. Desalination; environmental technology; Exact sciences and technology; fatty acids; Fundamental and applied biological sciences. Psychology; General purification processes; high-rate algal ponds; Hydrogen-Ion Concentration; lipid content; Lipid Metabolism - radiation effects; lipids; Lipids - analysis; Lipids - chemistry; Methods. Procedures. Technologies; microalgae; Microalgae - chemistry; Microalgae - metabolism; Others; Oxygen; Phytoplankton; Pollution; ponds; Reactors; Sewage; shade; Solar Energy; solar radiation; Temperature; upflow anaerobic sludge blanket reactor; Various methods and equipments; Wastewaters; Water treatment and pollution; British Isles; Drinking water treatment; Tropical zone; Upflow anaerobic sludge blanket reactor; domestic sewage; Disinfection; Lipids; Biomass; Fatty acids; Biological purification; Domestic waste water; Bioreactor; Ultraviolet radiation; high-rate algal ponds; Bacteria; Solar radiation; biodiesel
• ISSN: 1479-487X; 0959-3330; 1479-487X
• DOI: 10.1080/09593330.2014.902111

The objective of this paper is to compare the lipid content and composition of biomass produced by a consortium of microalgae and bacteria, cultivated under different solar radiation intensities and tropical conditions in pilot-scale high-rate ponds (HRPs) using domestic sewage as culture medium. The treatment system consisted of an upflow anaerobic sludge blanket reactor followed by UV disinfection and six HRPs covered with shading screens that blocked 9%, 18%, 30%, 60% and 80% of the solar radiation. The total lipid content does not vary significantly among the units, showing a medium value of 9.5%. The results show that blocking over 30% of the solar radiation has a negative effect on the lipid productivity. The units with no shading and with 30% and 60% of solar radiation blocking have statistically significant lipid productivities, varying from 0.92 to 0.96 g m ⁻² day ⁻¹. Besides radiation, other variables such as volatile suspended solids and chlorophyll- a are able to explain the lipid accumulation. The lipid profile has a predominance of C16, C18:1 and C18:3 acids. The unsaturation of fatty acids increases with the reduction in solar radiation. On the other hand, the effect of polyunsaturation is not observed, which is probably due to the presence of a complex and diverse biomass.